Impact of a Brazilian Nucleopolyhedrovirus Release on Anticarsia gemmatalis (Lepidoptera: Noctuidae), Secondary Insect Pests, and Predators on Soybean in Mexico

A 4-yr study (2000–2003) in southern Tamaulipas, Mexico, compared the impact of a Brazilian nucleopolyhedrovirus (AgNPV) and cypermethrin on Anticarsia gemmatalis Hübner, secondary pests, and arthropod predators in soybean fields. Areas treated with AgNPV had consistently low levels of A. gemmatalis beginning soon after application, while other arthropods within the agroecosystem remained in balance. Cypermethrin was highly effective against A. gemmatalis, but caused its rapid resurgence and increased secondary pests, mainly Pseudoplusia includens (Walker), as a result of elimination of the beneficial fauna. Densities of Nezara viridula (L.) were higher in the AgNPV plot than in the cypermethrin plot only during 2000, with no significant differences in the subsequent years. Overall (2000–2003), numbers of the predators Chrysoperla carnea (Stephens), Olla v-nigrum (Mulsant), hemipterans and lynx spiders were generally five times higher in the AgNPV plots than in the cypermethrin plots. Additional observations made only during 2003 showed a moderate presence of other predators (Calosoma sp. and Polistes sp.) and parasitism by Copidosoma truncatellum (Dalman) on A. gemmatalis and P. includens up to 40% in the AgNPV plot, in contrast with the cypermethrin plot, where these beneficials were not detected. This study showed the potential of AgNPV as a biocontrol-based IPM strategy for soybeans in Mexico.